Method for aligning light emitting element, method for manufacturing display device, and display device

Abstract

A method for aligning light-emitting elements, a method for manufacturing a display device, and a display device are provided. The method for aligning the light-emitting elements includes: providing a base substrate and a plurality of conductive patterns on the base substrate and spaced apart from each other; ejecting ink having a plurality of light-emitting elements dispersed therein onto the base substrate; positioning the plurality of light-emitting elements on the conductive patterns; and orienting one end of each of the plurality of light-emitting elements in a first direction.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0161605, filed on December 6, 2019, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the present disclosure relate to a method for aligning light-emitting elements, a method for manufacturing a display device using the method, and a display device, and, for example, relate to a light-emitting element alignment method, a method for manufacturing a display device using the method, and a display device, in which a plurality of light-emitting elements are aligned on a substrate by using conductive patterns spaced apart from each other on the substrate. Background Art

[0004] With the development of multimedia, the importance and demand of display devices are increasing. To cope with this increase, several types of display devices have been used, such as liquid crystal displays (LCDs) and / or organic light emitting diode (OLED) displays.

[0005] The display device includes a display panel such as an OLED panel or an LCD panel as a device for displaying an image. A light-emitting element may be included in the light-emitting display panel in the display panel. For example, a light-emitting diode (LED) may include an organic light-emitting diode (OLED) using an organic material as a fluorescent material, an inorganic light-emitting diode using an inorganic material as a fluorescent material, and the like. Summary of the Invention

[0006] One or more aspects of the embodiments of the present disclosure provide a light emitting element alignment method that aligns a light emitting element having fine (eg, micro) dimensions in a specific (predetermined or set) orientation on a substrate.

[0007] One or more aspects of the embodiments of the present disclosure further provide a method for manufacturing a display device including a plurality of light-emitting elements by transferring aligned light-emitting elements onto a target substrate. One or more aspects of the embodiments of the present disclosure further provide a display device manufactured using the manufacturing method of the embodiment.

[0008] It should be noted that the objects and embodiments of the present disclosure are not limited to the above-mentioned objects and embodiments, and other objects and embodiments of the present disclosure will be apparent to those skilled in the art from the following description.

[0009] According to an exemplary embodiment of the present disclosure, a method for aligning light-emitting elements includes: providing a base substrate and a plurality of conductive patterns on the base substrate, the plurality of conductive patterns being spaced apart from each other; ejecting ink in which a plurality of light-emitting elements are dispersed onto the base substrate, and positioning the plurality of light-emitting elements on the plurality of conductive patterns; and orienting the plurality of light-emitting elements by orienting one end of each of the plurality of light-emitting elements in a first direction.

[0010] In an exemplary embodiment, positioning the plurality of light emitting elements may include applying a first alignment signal to the plurality of conductive patterns to generate a first electromagnetic field on the plurality of conductive patterns; and positioning at least a portion of the plurality of light emitting elements on the plurality of conductive patterns.

[0011] In an exemplary embodiment, the plurality of light emitting elements may each independently include a conductive ball, the first electromagnetic field applies an attractive force to the conductive ball, and positioning the plurality of light emitting elements may include placing the conductive balls of at least a portion of the plurality of light emitting elements on the plurality of conductive patterns.

[0012] In an exemplary embodiment, a first alignment electrode and a second alignment electrode may be further arranged on the base substrate, the first alignment electrode and the second alignment electrode being spaced apart from each other in a first direction, and orienting the plurality of light emitting elements may include applying a second alignment signal to the first alignment electrode and the second alignment electrode to generate a second electromagnetic field on the base substrate and change the position and / or orientation of the plurality of light emitting elements.

[0013] In an exemplary embodiment, directing the plurality of light emitting elements may include applying a third alignment signal to the plurality of conductive patterns to generate a third electromagnetic field that is stronger than the first electromagnetic field.

[0014] In an exemplary embodiment, in directional multiple light-emitting elements, one end of each of the multiple light-emitting elements positioned on the multiple conductive patterns can be oriented in a first direction, and a plurality of light-emitting elements that are not positioned or partially positioned on the multiple conductive patterns can be moved and placed on the multiple conductive patterns, and one end of each of the multiple light-emitting elements moved and placed on the multiple conductive patterns can be oriented in the first direction.

[0015] In an exemplary embodiment, each of the plurality of light emitting elements may have a major axis extending in one direction and may be oriented such that the major axis is in a first direction.

[0016] In exemplary embodiments, a diameter of each of the plurality of light emitting elements may be greater than a diameter of each of the plurality of conductive patterns.

[0017] In an exemplary embodiment, the plurality of conductive patterns may be spaced apart from each other in a first direction and in a second direction intersecting the first direction, the first distance may be a distance between the plurality of conductive patterns spaced apart from each other in the first direction, and the first distance may be longer than a length of a major axis of each of the plurality of light emitting elements.

[0018] In an exemplary embodiment, the second distance may be a distance between a plurality of conductive patterns spaced apart from each other in the second direction, and the second distance may be shorter than a length of a major axis of each of the plurality of light emitting elements and may be longer than a diameter of each of the plurality of light emitting elements.

[0019] In an exemplary embodiment, the plurality of light emitting elements may include a first semiconductor layer, a second semiconductor layer, and an active layer located between the first semiconductor layer and the second semiconductor layer, and the first semiconductor layer, the active layer, and the second semiconductor layer may be stacked in another direction perpendicular to one direction in which the plurality of light emitting elements extend.

[0020] In an exemplary embodiment, the plurality of conductive patterns may include a plurality of first conductive patterns spaced apart from each other in a first direction and a plurality of second conductive patterns spaced apart from each other in the first direction, and wherein the plurality of second conductive patterns are spaced apart from the plurality of first conductive patterns in a second direction intersecting the first direction.

[0021] In an exemplary embodiment, the plurality of light-emitting elements may include a first light-emitting element and a second light-emitting element, and in positioning the plurality of light-emitting elements, a third electromagnetic field may be generated on the plurality of first conductive patterns, and the first light-emitting element may be positioned on the plurality of first conductive patterns, and a first electromagnetic field may be generated on the plurality of second conductive patterns, and the second light-emitting element may be positioned on the plurality of second conductive patterns.

[0022] According to an exemplary embodiment of the present disclosure, a method for manufacturing a display device includes: providing a base substrate and a plurality of conductive patterns on the base substrate, the plurality of conductive patterns being spaced apart from each other; ejecting ink in which a plurality of light-emitting elements are dispersed onto the base substrate, each of the plurality of light-emitting elements having a shape extending in one direction; generating a first electromagnetic field on the plurality of conductive patterns and positioning the plurality of light-emitting elements on the plurality of conductive patterns; generating a second electromagnetic field on the base substrate in a first direction and orienting the plurality of light-emitting elements; and transferring the plurality of light-emitting elements onto a substrate.

[0023] In an exemplary embodiment, the plurality of light emitting elements may include conductive balls, the first electromagnetic field applies an attractive force to the conductive balls, and positioning the plurality of light emitting elements may include seating the conductive balls on the plurality of conductive patterns.

[0024] In an exemplary embodiment, orienting the plurality of light emitting elements may include rotating the plurality of light emitting elements by the second electromagnetic field such that a direction in which each of the plurality of light emitting elements extends is substantially parallel to the first direction.

[0025] In an exemplary embodiment, the plurality of light emitting elements may be spaced apart from each other in a first direction and a second direction intersecting the first direction, and a length of each of the plurality of light emitting elements in one direction may be longer than a distance between adjacent ones of the plurality of light emitting elements in the second direction.

[0026] In example embodiments, a distance between adjacent ones of the plurality of light emitting elements in the first direction may be shorter than a length of a major axis of each of the plurality of light emitting elements.

[0027] According to an exemplary embodiment of the present disclosure, a display device includes: a first substrate; a semiconductor layer on the first substrate and including an active material layer of a driving transistor; a gate insulating layer on the semiconductor layer; a first gate conductive layer on the gate insulating layer and including a gate electrode of the driving transistor; a first interlayer insulating layer on the first gate conductive layer; a first data conductive layer on the first interlayer insulating layer and including a source electrode / drain electrode of the driving transistor; a second interlayer insulating layer on the first data conductive layer; a second data conductive layer on the second interlayer insulating layer and including a first conductive line in contact with the source electrode / drain electrode of the driving transistor; a first planarization layer on the second data conductive layer; a first electrode and a second electrode on the first planarization layer and spaced apart from each other; and a light-emitting element, wherein both ends of the light-emitting element are respectively on the first electrode and the second electrode, wherein the light-emitting element has a shape extending in one direction, and the light-emitting element includes a first electrode unit and a second electrode unit respectively located at both ends of the light-emitting element in one direction, and also includes a conductive ball on the first electrode unit and in direct contact with the first electrode.

[0028] In example embodiments, the light emitting element may include a first semiconductor layer, a second semiconductor layer, and an active layer therebetween, and the first semiconductor layer, the active layer, and the second semiconductor layer may be stacked in another direction perpendicular to one direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other aspects and features of embodiments of the present disclosure will become more apparent by describing in more detail exemplary embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0030] Figure 1 is a plan view of a display device according to an embodiment;

[0031] Figure 2is a schematic plan view showing a pixel included in a display device according to an embodiment;

[0032] Figure 3 is an equivalent circuit diagram of one pixel included in the display device according to the embodiment;

[0033] Figure 4 is a schematic diagram illustrating a process of manufacturing a display device according to an embodiment;

[0034] Figure 5 is a plan view showing aligned light emitting elements according to an embodiment;

[0035] Figure 6 is a flowchart illustrating a method of aligning a light emitting element according to an embodiment;

[0036] Figure 7 is a plan view illustrating one operation of a method of aligning a light emitting element according to an embodiment;

[0037] Figure 8 shows a schematic diagram illustrating one operation of a method of aligning a light emitting element according to an embodiment;

[0038] Figure 9 is a schematic cross-sectional view of a light emitting element according to an embodiment;

[0039] Figures 10 to 12 is a schematic diagram illustrating one operation of a method of aligning a light emitting element according to an embodiment;

[0040] Figures 13 to 15 is a schematic diagram illustrating one operation of a method of aligning a light emitting element according to an embodiment;

[0041] Figure 16 is a plan view showing a base substrate on which a light emitting element is aligned according to an embodiment;

[0042] Figure 17 is a cross-sectional view showing one sub-pixel of a display device according to an embodiment;

[0043] Figure 18 is a plan view showing a base substrate on which a light emitting element is aligned according to another embodiment;

[0044] Figures 19 to 21 is a schematic diagram illustrating some operations of a method of aligning a light emitting element according to another embodiment; and

[0045] Figure 22 is a plan view showing a base substrate on which a light emitting element is aligned according to another embodiment. DETAILED DESCRIPTION

[0046] Embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the present disclosure are shown. However, the subject matter of the present disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art.

[0047] It will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate (without any intervening layers), or intervening layers may also be present. Throughout the specification, the same reference numerals refer to the same components.

[0048] It will be understood that although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, the first element discussed below may be referred to as the second element without departing from the teachings of the present disclosure. Similarly, the second element may also be referred to as the first element.

[0049] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0050] Figure 1 is a schematic plan view of a display device according to an embodiment. Figure 2 is a schematic plan view illustrating a pixel included in a display device according to an embodiment.

[0051] Reference Figure 1 and Figure 2 The display device 10 may display a video or a still image. The display device 10 may refer to any suitable electronic device having a display screen. For example, the display device 10 may include a television, a notebook computer, a monitor, a billboard, an Internet of Things (IoT) device, a mobile phone, a smartphone, a tablet personal computer (PC), an electronic watch, a smartwatch, a watch phone, a head-mounted display, a mobile communication terminal, an electronic notebook, an e-book reader, a portable multimedia player (PMP), a navigation device, a game console, a digital camera, a video camera, etc., provided with a display screen.

[0052] The display device 10 may include a display panel that provides a display screen. Examples of the display panel may include an inorganic light-emitting diode display panel, an organic light-emitting display panel, a quantum dot light-emitting display panel, a plasma display panel, a field emission display panel, and the like. In the following description, an inorganic light-emitting diode display panel is used as an example of a display panel. However, the present disclosure is not limited thereto, and other suitable display panels may be used as long as substantially the same technical spirit is applicable.

[0053] The shape of the display device 10 can be changed in various suitable ways. For example, the display device 10 can have a horizontally long rectangle, a vertically long rectangle, a square, a quadrilateral with rounded corners (vertices), other polygons, a circle, etc. The shape of the display area DPA of the display device 10 can be similar to the overall shape of the display device 10. Figure 1 , the display device 10 and the display area DPA are both shown in the shape of a horizontally long rectangle, but the present disclosure is not limited thereto.

[0054] The display device 10 may include a display area DPA and a non-display area NDA. The display area DPA is an area where a screen (e.g., an image) can be displayed, and the non-display area NDA is an area where a screen (e.g., an image) is not displayed. The display area DPA may be referred to as an active area, and the non-display area NDA may be referred to as a non-active area. The display area DPA may occupy approximately the center of the display device 10 (e.g., may be substantially in the center of the display device 10).

[0055] The non-display area NDA may be disposed around the display area DPA. The non-display area NDA may completely or partially surround the display area DPA. The display area DPA may have a rectangular shape, and the non-display area NDA may be adjacent to four sides of the display area DPA. The non-display area NDA may form a frame of the display device 10. A line and / or circuit driving unit included in the display device 10 may be located in the non-display area NDA, and / or external devices may be installed in the non-display area NDA.

[0056] The display area DPA may include a plurality of pixels PX. The plurality of pixels PX may be arranged in a matrix direction (e.g., arranged in a matrix configuration). When viewed from the top, the shape of one or more of the pixels PX may be a rectangle or a square. However, the present disclosure is not limited thereto, and the shape of one or more pixels PX may be a rhombus with each side tilted in one direction. The pixels PX may be alternately arranged in a stripe pattern or a pentile pattern.

[0057] Each pixel PX may include multiple sub-pixels PXn. For example, a pixel PX may include a first sub-pixel PX1, a second sub-pixel PX2, and a third sub-pixel PX3. Each of the sub-pixels PXn may include at least one light-emitting element 500 to display light of a specific (or set) wavelength range. The light-emitting elements 500 in the sub-pixels PXn may include different materials to emit light of different wavelength ranges. As an example, the light-emitting element 500 of the first sub-pixel PX1 may include a material that emits (e.g., is configured to emit) a first light having a center wavelength range of a first wavelength, the light-emitting element 500 of the second sub-pixel PX2 may include a material that emits (e.g., is configured to emit) a second light having a center wavelength range of a second wavelength, and the light-emitting element 500 of the third sub-pixel PX3 may include a material that emits (e.g., is configured to emit) a third light having a center wavelength range of a third wavelength. Therefore, the first sub-pixel PX1 may emit light of a first color, the second sub-pixel PX2 may emit light of a second color, and the third sub-pixel PX3 may emit light of a third color. In some embodiments, the first color of light may be blue light having a center wavelength range of 450 nm to 495 nm, the second color of light may be green light having a center wavelength range of 495 nm to 570 nm, and the third color of light may be red light having a center wavelength range of 620 nm to 752 nm.

[0058] However, the present disclosure is not limited thereto. In some embodiments, the first sub-pixel PX1, the second sub-pixel PX2, and the third sub-pixel PX3 may include the same type (or kind) of light emitting element 500 to emit light of substantially the same color. In addition, Figure 2 It is shown that the pixel PX includes three sub-pixels PXn. However, the present disclosure is not limited thereto, and the pixel PX may include a greater number of sub-pixels PXn.

[0059] Each of the pixels PX of the display device 10 also includes a pixel driving circuit. The lines described above may pass through the pixel PX or be adjacent to the pixel PX to apply a driving signal to the pixel driving circuit. Each of the pixel driving circuits may include a transistor and a capacitor. The number of transistors and capacitors in each pixel driving circuit can vary differently. The exemplary pixel driving circuit will be described below using a 3T1C structure, where the term "3T1C" refers to including three transistors and one capacitor. However, the present disclosure is not limited thereto, and various other appropriately modified pixel PX structures may be used, such as a 2T1C (two transistors and one capacitor) structure, a 7T1C (seven transistors and one capacitor) structure, and / or a 6T1C (six transistors and one capacitor) structure.

[0060] Figure 3 is an equivalent circuit diagram of one pixel included in the display device according to the embodiment.

[0061] Reference Figure 3 , each pixel PX of the display device according to the embodiment includes three transistors DT, SCT, and SST and one storage capacitor Cst, in addition to the light emitting diode EL.

[0062] The light emitting diode EL emits light according to the current supplied by the driving transistor DT. The light emitting diode EL includes a first electrode, a second electrode and a light emitting element 500 (see FIG. 5 ) interposed therebetween. Figure 4 ). The light emitting element 500 can emit light of a specific (or set) wavelength range according to the electrical signal transmitted from the first electrode and the second electrode. This will be described in more detail below.

[0063] The light emitting diode EL has one end coupled to the first source / drain electrode of the driving transistor DT and the other end coupled to the first voltage line VSL, through which a low-level voltage (first power supply voltage) lower than the high-level voltage (second power supply voltage) of the second voltage line VDL is supplied. As used herein, the expression "first source / drain electrode" refers to the first source electrode or the first drain electrode.

[0064] The driving transistor DT adjusts the current flowing from the second voltage line VDL through which the second power supply voltage is supplied to the light emitting diode EL according to the voltage difference between the gate electrode and the source electrode of the driving transistor DT. The driving transistor DT may have a gate electrode coupled to the first source / drain electrode of the scanning transistor SCT, a first source / drain electrode coupled to the first electrode of the light emitting diode EL, and a second source / drain electrode coupled to the second voltage line VDL to which the second power supply voltage is applied.

[0065] The scanning transistor SCT is turned on according to the scanning signal of the scanning line SCL to couple the data line DTL to the gate electrode of the driving transistor DT. The scanning transistor SCT may have a gate electrode coupled to the scanning line SCL, a first source / drain electrode coupled to the gate electrode of the driving transistor DT, and a second source / drain electrode coupled to the data line DTL.

[0066] The sensing transistor SST can be turned on according to a sensing signal of the sensing line SSL to couple the reference voltage line RVL to the first source / drain electrode of the driving transistor DT. The sensing transistor SST may have a gate electrode coupled to the sensing line SSL, a first source / drain electrode coupled to the reference voltage line RVL, and a second source / drain electrode coupled to the first source / drain electrode of the driving transistor DT.

[0067] In an embodiment, the first source / drain electrodes of the plurality of transistors DT, SCT, and SST may be source electrodes, and the second source / drain electrodes of the plurality of transistors DT, SCT, and SST may be drain electrodes, respectively. However, the present disclosure is not limited thereto, and the opposite is also possible.

[0068] The storage capacitor Cst is formed between the gate electrode and the first source / drain electrode of the driving transistor DT. The storage capacitor Cst stores a voltage difference between the gate voltage of the driving transistor DT and the first source / drain voltage.

[0069] Each of the plurality of transistors DT, SCT, and SST may be formed as a thin film transistor. Figure 3 In the present disclosure, the plurality of transistors DT, SCT, and SST will be described as being formed as n-type metal oxide semiconductor field effect transistors (MOSFETs), but the present disclosure is not limited thereto. For example, the plurality of transistors DT, SCT, and SST may be formed as p-type MOSFETs. In some embodiments, some of the transistors DT, SCT, and SST may be formed as n-type MOSFETs, and the others of the transistors DT, SCT, and SST may be formed as p-type MOSFETs.

[0070] As mentioned above, Figure 2 As shown in FIG, the display device 10 may include a plurality of pixels PX in the display area DPA, and each of the plurality of pixels PX may include a plurality of sub-pixels PXn arranged in one direction. Figure 2 As shown in , a plurality of sub-pixels PXn can be arranged in a first direction DR1 and a second direction DR2. Similarly, the light-emitting elements 500 in the sub-pixels PXn can be arranged in the display area DPA in one or more directions corresponding to the sub-pixels PXn. A plurality of light-emitting elements 500 can be in the sub-pixels PXn and can be spaced apart from each other in the first direction DR1 and the second direction DR2. In contrast to the method of placing the light-emitting elements 500 directly on the target substrate of the display device 10, a method of transferring the light-emitting elements 500 aligned on another substrate (e.g., a base substrate or a transfer substrate) can be used to manufacture such a display device 10, but the present disclosure is not limited thereto.

[0071] Figure 4 is a schematic diagram illustrating a process of manufacturing a display device according to an embodiment.

[0072] Reference Figure 2 and Figure 4, the method for manufacturing the display device 10 according to the embodiment can be performed in a process of transferring the light-emitting element 500 aligned on the base substrate BS to the target substrate SUB. The light-emitting element 500 can be aligned in one direction and arranged on the base substrate BS. The light-emitting element 500 aligned on the base substrate BS can then be transferred to the target substrate SUB of the display device 10 using a transfer device TD. The transfer device TD can transfer the light-emitting element 500 arranged on the base substrate BS to the target substrate SUB by moving along the third direction DR3 and the first direction DR1. The target substrate SUB can be a substrate in which an area corresponding to the pixel PX or sub-pixel PXn of the display device 10 is defined, and the light-emitting element 500 can be transferred to the area of ​​the target substrate SUB corresponding to the pixel PX or sub-pixel PXn. In addition, circuit elements for driving the pixel PX and / or sub-pixel PXn can also be set on the target substrate SUB.

[0073] Here, the light-emitting elements 500 may not be transferred individually by the transfer device TD. Instead, two or more of the light-emitting elements 500 located on the base substrate BS may be transferred to the target substrate SUB in the same process (e.g., during the same action). In order to accurately transfer the light-emitting elements 500 to the pixels PX or sub-pixels PXn defined on the target substrate SUB, the light-emitting elements 500 may be aligned on the base substrate BS to correspond to the pixels PX or sub-pixels PXn of the display device 10.

[0074] Figure 5 is a plan view illustrating aligned light emitting elements according to an embodiment. Figure 5 Schematically shows the arrangement Figure 4 A plurality of light emitting elements 500 are formed on a base substrate BS.

[0075] Reference Figure 5 , the light emitting elements 500 may be arranged on the base substrate BS in at least one direction. The light emitting elements 500 may be arranged in a first direction DR1 and a second direction DR2, and any light emitting element 500 may be spaced apart from other adjacent light emitting elements 500 in the first direction DR1 and the second direction DR2. In order to arrange the light emitting elements 500 on the base substrate BS to correspond to the sub-pixels PXn defined on the target substrate SUB, the plurality of light emitting elements 500 may be aligned in the first direction DR1 and the second direction DR2 so that the light emitting elements 500 are spaced apart from each other at a uniform (e.g., substantially uniform) distance and / or are oriented in a uniform (e.g., substantially uniform) direction.

[0076] To this end, the method of aligning the light-emitting elements 500 according to the embodiment may include determining the position where the light-emitting elements 500 will be placed and orienting the light-emitting elements 500 in one direction. The process of aligning the light-emitting elements 500 on the base substrate BS may include determining the position where the light-emitting elements 500 will be placed, arranging the light-emitting elements 500 uniformly (e.g., substantially uniformly) to be spaced apart from each other, and rotating and moving the light-emitting elements 500 based on the initial arrangement so as to orient the light-emitting elements 500 in a uniform (e.g., substantially uniform) direction.

[0077] For example, as shown in the drawings, a plurality of conductive patterns DP may be arranged on a base substrate BS, and the light-emitting element 500 may have a specific (or predetermined) portion to be placed on the conductive pattern DP. A method of aligning the light-emitting element 500 according to an embodiment may include providing a base substrate BS on which a plurality of conductive patterns DP are spaced apart from each other, and placing the light-emitting element 500 on the base substrate BS. The light-emitting element 500 may have a specific (or predetermined) portion placed on the conductive pattern DP, and thus the distance between the aligned light-emitting elements 500 may be uniform (e.g., substantially uniform).

[0078] In addition, in some embodiments, each of the light-emitting elements 500 may have a shape extending in one direction, and the shape may have two axes of different lengths, for example, a major axis and a minor axis. The plurality of light-emitting elements 500 may have an orientation in the direction of their major axis, and thus the plurality of light-emitting elements 500 on the base substrate BS may be aligned in a constant orientation (for example, the same orientation). For example, the light-emitting element 500 may be oriented so that the major axis points in the second direction DR2, while a specific portion of the light-emitting element 500 is placed on the conductive pattern DP. The method of aligning the light-emitting element 500 according to the embodiment may include aligning the light-emitting element 500 using the conductive pattern DP on the base substrate BS so that the light-emitting elements 500 are spaced apart from each other at a regular (for example, substantially regular) distance in a constant orientation (for example, the same orientation). Therefore, the light-emitting elements 500 transferred to the target substrate SUB by a subsequent transfer process can be arranged at precise positions to correspond to the plurality of sub-pixels PXn.

[0079] The method of aligning the light emitting element 500 will be described in more detail below with further reference to other figures herein.

[0080] Figure 6 is a flowchart illustrating a method of aligning a light emitting element according to an embodiment.

[0081] Reference Figure 6According to an embodiment, the method of aligning the light emitting elements 500 may include: providing a base substrate BS having a plurality of conductive patterns DP formed thereon (S100); ejecting ink having a plurality of light emitting elements 500 dispersed therein onto the base substrate BS (S200); placing the plurality of light emitting elements 500 on the conductive patterns DP (S300); and orienting the light emitting elements 500 in one direction (S400).

[0082] In an embodiment, the light emitting element 500 may be ejected onto the base substrate BS using an inkjet printing method. The light emitting element 500 may be provided in a fine (eg, micro) size and dispersed in ink (see Figure 8 The "Ink" in the conductive pattern DP is formed by a plurality of layers of ink (S300), and the ink can be ejected onto the base substrate BS. The light-emitting elements 500 dispersed in the ink Ink can be aligned on the base substrate BS by an operation of determining the position where the light-emitting elements 500 will be placed and an operation of orienting the light-emitting elements 500 in one direction. The operation of determining the position where the light-emitting elements 500 will be placed makes the light-emitting elements 500 have a set or specific portion placed on the conductive pattern DP. Placing the light-emitting elements 500 on the conductive pattern DP (S300) is an operation of determining the position where the light-emitting elements 500 will be arranged. Subsequently, the light-emitting elements 500 can be aligned by orienting the light-emitting elements 500 in one direction. The method of aligning the light-emitting elements 500 will be described in more detail with reference to other drawings.

[0083] As used herein, the term "operation" may refer to actions of a method of the present embodiments.

[0084] Figure 7 is a plan view illustrating one operation of a method of aligning a light emitting element according to an embodiment.

[0085] First, refer to Figure 7 A base substrate BS and a plurality of conductive patterns DP on the base substrate BS are provided (S100). The base substrate BS can provide a space for arranging the conductive patterns DP so that the light-emitting elements 500 can be placed on the conductive patterns DP. The material of the base substrate BS is not particularly limited as long as it can provide a space for aligning the light-emitting elements 500. As an example, the base substrate BS may include glass, quartz, and / or a polymer resin, or may be a ceramic substrate, a glass wafer, a silicon wafer, or the like.

[0086] In some embodiments, alignment electrodes ED1 and ED2 may be further provided on the base substrate BS (see Figure 13) and a plurality of lines capable of applying electrical signals. The plurality of lines can be electrically coupled to the conductive pattern DP to apply electrical signals thereto, and the alignment electrodes ED1 and ED2 can generate an electric field and / or a magnetic field on the base substrate BS. As will be described in greater detail below, when an electrical signal is applied to the conductive pattern DP, the light-emitting element 500 can be moved and thereby partially positioned on the conductive pattern DP. When an electrical signal is applied to the alignment electrodes ED1 and ED2, the light-emitting element 500 can be rotated or moved and thereby oriented in a certain direction.

[0087] A plurality of conductive patterns DP are arranged on the base substrate BS. The conductive patterns DP may be spaced apart from each other at regular (e.g., substantially regular) distances. For example, the conductive patterns DP may be spaced apart from each other in the first direction DR1 and the second direction DR2 to form a lattice pattern on the entire base substrate BS. In this figure, the conductive patterns DP are shown as being spaced apart from each other in the first direction DR1 and the second direction DR2, wherein the first direction DR1 and the second direction DR2 intersect each other (e.g., are perpendicular to each other), but the present disclosure is not limited thereto. In some embodiments, the conductive patterns DP may be spaced apart from each other along a direction inclined relative to the first direction DR1 and the second direction DR2. In addition, Figure 7 The conductive pattern DP is shown only in a partial area of ​​the base substrate BS. However, the present disclosure is not limited thereto, and the conductive pattern DP may be arranged on the entire base substrate BS. The size of the conductive pattern DP and the distance between the conductive patterns DP will be described in more detail below.

[0088] The conductive pattern DP may include a conductive material so that an electrical signal can be applied to the conductive pattern DP. For example, the conductive pattern DP may include a metal and may be electrically coupled to a plurality of lines included in the base substrate BS. Multiple conductive patterns DP may be coupled simultaneously (or in parallel) to lines to which the same electrical signal is applied, but the present disclosure is not limited thereto. In some embodiments, some of the conductive patterns DP may be coupled to lines different from those of other conductive patterns DP, and thus different electrical signals may be applied to the conductive patterns DP.

[0089] In some embodiments, the position of the conductive pattern DP on the base substrate BS may vary according to the arrangement of the sub-pixels PXn of the display device 10 on which the light-emitting element 500 is to be transferred. The light-emitting element 500 may be transferred to the target substrate SUB of the display device 10, and the area corresponding to the pixel PX or sub-pixel PXn of the display device 10 may be defined on the target substrate SUB. The light-emitting element 500 may be aligned on the base substrate BS so that the light-emitting element 500 may be transferred to the corresponding area defined on the target substrate SUB. To this end, the conductive pattern DP may also correspond to the area defined on the target substrate SUB. For example, in a process of manufacturing the display device 10 using a method of aligning the light-emitting element 500, the position of the conductive pattern DP on the base substrate BS and the distance between the conductive patterns DP may vary according to the arrangement of the pixel PX and / or sub-pixel PXn of the display device 10. However, the present disclosure is not limited thereto.

[0090] Subsequently, ink in which the plurality of light emitting elements 500 are dispersed is ejected onto the base substrate BS ( S200 ).

[0091] Figure 8 A schematic diagram illustrating one operation of a method of aligning a light emitting element according to an embodiment is shown.

[0092] Reference Figure 8 , ink Ink in which a plurality of light-emitting elements 500 are dispersed is ejected onto the base substrate BS. In an embodiment, the light-emitting elements 500 may be ejected onto the base substrate BS by an inkjet printing method. The light-emitting elements 500 may be randomly positioned such that the directions of the long axes of the light-emitting elements 500 are not uniform and the distances between the light-emitting elements 500 are not constant. Subsequently, the light-emitting elements 500 may be aligned uniformly (e.g., substantially uniformly) by varying (e.g., changing) the orientation and position of each of the light-emitting elements 500.

[0093] In some embodiments, the light-emitting elements 500 ejected by the inkjet printing method may be surface treated so that the light-emitting elements 500 do not aggregate with each other, or an ultrasonic treatment may be performed on the base substrate BS. When the light-emitting elements 500 aggregate due to the attraction applied therebetween, the plurality of light-emitting elements 500 may not be aligned uniformly (e.g., substantially uniformly) on the base substrate BS. In order to prevent or reduce the possibility of aggregation of the light-emitting elements 500, dispersion may be performed by surface treatment or a physical method such as ultrasonic treatment. However, the present disclosure is not limited thereto.

[0094] In some embodiments, the light-emitting elements 500 can each independently be a light-emitting diode (LED) or an LED chip containing an inorganic semiconductor. In an exemplary embodiment, the light-emitting element 500 can be a micro-LED chip having a shape extending in one direction and having micrometer or nanometer dimensions. When the light-emitting element 500 is an LED chip, the light-emitting element 500 can include a semiconductor layer doped with impurities of any conductivity type (e.g., p-type or n-type), and can receive an electrical signal applied from an external power source to emit light in a specific (or set) wavelength range.

[0095] Figure 9 is a schematic cross-sectional view of a light emitting element according to an embodiment. Figure 9 is a cross-sectional view schematically showing a light emitting element 500 according to an embodiment.

[0096] Reference Figure 9 And refer to Figure 8 , the light-emitting element 500 may have a shape extending in one direction. The light-emitting element 500 may include a long axis corresponding to the extension direction and a short axis perpendicular to the long axis. As an example, the aspect ratio of the light-emitting element 500 may have a range of 1.2:1 to 100:1. The long axis of the light-emitting element 500 may have a length in the range of several microns to several hundred microns. For example, the length of the long axis of the light-emitting element 500 may be in the range of 1μm to 800μm (or 1μm to 500μm). In some embodiments, the length of the long axis of the light-emitting element 500 may be in the range of 10μm to 300μm. However, the present disclosure is not limited thereto.

[0097] The light-emitting element 500 may have a structure in which a plurality of inorganic semiconductor layers are stacked. In an embodiment, in the light-emitting element 500, the direction in which the plurality of inorganic semiconductor layers are stacked and the direction in which the long axis of the light-emitting element 500 extends may be perpendicular to each other (e.g., substantially perpendicular). For example, when the light-emitting element 500 has a shape extending in one direction, the inorganic semiconductor layers may be stacked in a direction perpendicular to (e.g., substantially perpendicular to) the one direction. The plurality of semiconductor layers may have a shape extending in the long axis direction of the light-emitting element 500 and may be stacked in the thickness direction of the light-emitting element 500, the thickness direction of the light-emitting element 500 being perpendicular to (e.g., substantially perpendicular to) the extension direction.

[0098] In some embodiments, the light emitting element 500 may include a lower substrate 501, a first semiconductor layer 510, a second semiconductor layer 520, an active layer 530, a first electrode unit 560, a second electrode unit 570, and an outer cover 580. In some embodiments, the light emitting element 500 according to the embodiment may include a conductive ball DB on either the first electrode unit 560 or the second electrode unit 570.

[0099] The lower substrate 501 may be a growth substrate for growing the first semiconductor layer 510. As an example, the lower substrate 501 may include a transparent substrate such as sapphire (Al2O3) and / or glass. However, the present disclosure is not limited thereto. In some embodiments, the lower substrate 501 may include a conductive substrate such as GaN, SiC, ZnO, Si, GaP, and / or GaAs.

[0100] The first semiconductor layer 510 may include an n-type semiconductor. As an example, when the light emitting element 500 emits light in a blue wavelength range, the first semiconductor layer 510 may include a semiconductor having a chemical formula of Al x Ga y In 1-x-y N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, the first semiconductor layer 510 may include one or more of AlGaInN, GaN, AlGaN, InGaN, AlN, and InN, each independently doped with an n-type dopant. The first semiconductor layer 510 may be doped with an n-type dopant. As an example, the n-type dopant may include Si, Ge, Sn, etc. In an exemplary embodiment, the first semiconductor layer 510 may include n-GaN doped with Si.

[0101] The second semiconductor layer 520 may be disposed on the active layer 530, which will be described in more detail below. The second semiconductor layer 520 may include a p-type semiconductor. As an example, when the light emitting element 500 emits light in a blue wavelength range or a green wavelength range, the second semiconductor layer 520 may include a p-type semiconductor. x Ga y In 1-x-y The second semiconductor layer 520 may be a semiconductor material having a p-type N structure (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, the second semiconductor layer 520 may include one or more of AlGaInN, GaN, AlGaN, InGaN, AlN, and InN, each independently doped with a p-type dopant. When the second semiconductor layer 520 is doped with a p-type dopant, the p-type dopant may be, for example, Mg, Zn, Ca, Se, Ba, or the like. In an exemplary embodiment, the second semiconductor layer 520 may include p-GaN p-doped with Mg.

[0102] exist Figure 9 , the first semiconductor layer 510 and the second semiconductor layer 520 are shown as being formed as a single layer, but the present disclosure is not limited thereto. In some embodiments, the first semiconductor layer 510 and the second semiconductor layer 520 may include more than one layer, such as a capping layer (e.g., a cladding layer) and / or a tensile strain barrier reduction (TSBR) layer. This will be described in more detail below with reference to other figures herein.

[0103] The active layer 530 may be disposed between the first semiconductor layer 510 and the second semiconductor layer 520. The active layer 530 may be disposed only on a portion of the first semiconductor layer 510, and the contact layer 573 of the second electrode unit 570 may be disposed on a portion of the first semiconductor layer 510 where the active layer 530 is not disposed. The active layer 530 may include a material having a single quantum well structure or a multiple quantum well structure. When the active layer 530 includes a material having a multiple quantum well structure, the active layer 530 may have a structure in which multiple quantum layers and multiple well layers are alternately stacked. The active layer 530 may emit light through electron-hole pair recombination in response to an electrical signal applied through the first semiconductor layer 510 and the second semiconductor layer 520. As an example, when the active layer 530 emits light in the blue wavelength range, the active layer 530 may include a material such as AlGaN or AlGaInN. For example, when the active layer 530 has a multi-quantum well structure (e.g., a structure in which quantum layers and well layers are alternately stacked), the quantum layers may include materials such as AlGaN and / or AlGaInN, and the well layers may include materials such as GaN and / or AlInN. In an exemplary embodiment, the active layer 530 may include AlGaInN as a quantum layer and also include AlInN as a well layer. As described above, the active layer 530 may emit blue light having a central wavelength range of 450 nm to 495 nm.

[0104] However, the present disclosure is not limited thereto, and the active layer 530 may have a structure in which semiconductor materials having large band gap energy and semiconductor materials having small band gap energy are alternately stacked, and may include different III-V semiconductor materials depending on the wavelength range of light to be emitted. In addition, the light emitted by the active layer 530 is not limited to light in the blue wavelength range. In some embodiments, the active layer 530 may emit light in the red wavelength range or the green wavelength range.

[0105] The light-emitting element 500 has a shape extending in one direction and includes a first electrode unit 560 and a second electrode unit 570, respectively located at both ends of the extending direction of the light-emitting element 500. The first electrode unit 560 and the second electrode unit 570 may respectively include electrode layers 561 and 571 on the lower substrate 501, contact layers 563 and 573 on the first semiconductor layer 510 or the second semiconductor layer 520, and bridges 565 and 575 configured to electrically couple the electrode layers 561 and 571 to the contact layers 563 and 573, respectively. The first electrode unit 560 may include a first electrode layer 561, a first contact layer 563 on the second semiconductor layer 520, and a first bridge 565 configured to couple the first electrode layer 561 and the first contact layer 563. The second electrode unit 570 may include a second electrode layer 571, a second contact layer 573 on the first semiconductor layer 510, and a second bridge 575 configured to couple the second electrode layer 571 to the second contact layer 573.

[0106] The first electrode layer 561 and the second electrode layer 571 may be on the lower substrate 501. Figure 9 , the first electrode layer 561 and the second electrode layer 571 are shown as being located at both sides (e.g., at both ends) of the lower substrate 501, but the present disclosure is not limited thereto. The first electrode layer 561 and the second electrode layer 571 are terminals of the light-emitting element 500 and can be electrically coupled to electrodes on the sub-pixels PXn of the display device 10. While driving the display device 10, the first electrode layer 561 and the second electrode layer 571 can transmit electrical signals applied from the electrodes to the contact layers 563 and 573 through the bridge portions 565 and 575. The first electrode layer 561 and the second electrode layer 571 can each independently include a single layer of metal or a multilayer of metal. As an example, the first electrode layer 561 and the second electrode layer 571 can include one or more metals such as Al, Ti, Cr, Ni and / or Au, one or more alloys thereof, and the like.

[0107] The first contact layer 563 may be on the second semiconductor layer 520, and the second contact layer 573 may be in an exposed region of the first semiconductor layer 510 where the active layer 530 is not present. The first contact layer 563 and the second contact layer 573 may respectively transmit an electrical signal applied through the bridges 565 and 575 to the second semiconductor layer 520 and the first semiconductor layer 510. As an example, the first contact layer 563 and the second contact layer 573 may include one or more metals such as Al, Ti, Cr, Ni, and / or Au, one or more alloys thereof, and the like.

[0108] The first bridge portion 565 can electrically connect the first electrode layer 561 and the first contact layer 563, and the second bridge portion 575 can electrically connect the second electrode layer 571 and the second contact layer 573. The first bridge portion 565 and the second bridge portion 575 can each independently include one or more metals such as Al, Ti, Cr, Ni and / or Au, or one or more alloys thereof. However, the present disclosure is not limited thereto. In some embodiments, the bridge portions 565 and 575 can be omitted from the first electrode unit 560 and the second electrode unit 570, respectively.

[0109] The light emitting element 500 may further include an insulating film surrounding the plurality of semiconductor layers. However, the present disclosure is not limited thereto, and the insulating film may be omitted.

[0110] The outer cover 580 may be on the lower substrate 501 to protect the plurality of semiconductor layers. The outer cover 580 may include a transparent material so that light generated in the active layer 530 can be emitted. For example, the outer cover 580 may include glass, quartz, a transparent polymer resin, etc. However, the present disclosure is not limited thereto.

[0111] In some embodiments, the light-emitting element 500 may include a region surrounded by the outer cover 580, and the region formed between the semiconductor layer and the outer cover 580 may be further filled with other materials. For example, a material for changing the characteristics of the light emitted from the active layer 530 may be further provided in the region surrounded by the outer cover 580. In some embodiments, the light-emitting element 500 may include a phosphor or quantum dots in this region to convert the light emitted from the active layer 530 into light of a different color. In some cases, the light-emitting element 500 may include a scatterer in this region.

[0112] According to an embodiment, the light-emitting element 500 may include a conductive ball DB on either the first electrode layer 561 or the second electrode layer 571. In the light-emitting element 500 included in the display device 10, the first electrode unit 560 or the second electrode unit 570 and the conductive ball DB may be in contact with the electrode of the display device 10. When the conductive ball DB is on the first electrode layer 561 of the first electrode unit 560, the second electrode layer 571 of the second electrode unit 570 and the conductive ball DB in the light-emitting element 500 may be in direct contact (e.g., physical contact) with the electrode of the display device 10. The conductive ball DB may include a conductive material, and an electrical signal applied from the electrode of the display device 10 may be transmitted to the electrode units 560 and 570 of the light-emitting element 500, for example, to the first electrode layer 561 or the second electrode layer 571. As an example, the conductive ball DB of the light-emitting element 500 may include one or more metals such as Al, Ti, Cr, Ni, and / or Au, one or more alloys thereof, etc. However, the present disclosure is not limited thereto.

[0113] According to an embodiment, in the method of aligning the light emitting element 500, when an electric signal is applied to the conductive pattern DP of the base substrate BS, an electric field or a magnetic field may be formed on the conductive pattern DP, and the conductive ball DB of the light emitting element 500 may receive an attractive force due to the electric field or the magnetic field. Figure 8 As shown in the figure, the light-emitting elements 500 dispersed in the ink Ink can be initially positioned on the base substrate BS without a specific orientation. The light-emitting elements 500 (each of which has a shape extending in one direction) can be initially positioned so that the direction of the long axis is not constant and the light-emitting elements 500 do not correspond to the conductive pattern DP of the base substrate BS. When an electrical signal is applied to the conductive pattern DP to align the light-emitting elements 500, the electric field or magnetic field generated by the electrical signal can apply an attractive force to the conductive balls DB of the light-emitting elements 500. When the attractive force is applied to the conductive balls DB while the light-emitting elements 500 are dispersed in the ink Ink, some of the light-emitting elements 500 can be placed on the conductive pattern DP. This will be described in more detail with reference to other figures.

[0114] Figures 10 to 12 is a schematic diagram illustrating one operation of a method of aligning a light emitting element according to an embodiment.

[0115] Reference Figures 10 to 12 When ink Ink having light-emitting elements 500 dispersed therein is ejected onto the base substrate BS, the light-emitting elements 500 are positioned on the conductive pattern DP (S300). According to an embodiment, positioning the light-emitting elements 500 on the conductive pattern DP may include positioning at least some of the plurality of light-emitting elements 500 on the conductive pattern DP. As an example, positioning the light-emitting elements 500 on the conductive pattern DP may include applying a first alignment signal to the conductive pattern DP to form a first electromagnetic field EP1 on the conductive pattern DP, and then applying an attractive force to the conductive balls DB of the light-emitting elements 500.

[0116] In some embodiments, when the ink Ink is ejected onto the base substrate BS, the light-emitting elements 500 may be randomly positioned without a specific orientation. When a first alignment signal is applied to the conductive pattern DP of the base substrate BS, a first electromagnetic field EP1 may be generated on the conductive pattern DP comprising a conductive material (e.g., an electrically conductive material). The first electromagnetic field EP1 may be an electric field and / or a magnetic field generated by the first alignment signal, but the present disclosure is not limited thereto.

[0117] The first electromagnetic field EP1 generated on the conductive pattern DP can exert an attractive force on the conductive balls DB of the light-emitting elements 500 dispersed in the ink Ink. The conductive balls DB may include a conductive material (e.g., an electrically conductive material) to receive the attractive force caused by the first electromagnetic field EP1 generated by the first alignment signal, and the light-emitting elements 500 fluidly dispersed in the ink Ink may have positions that vary according to the attractive force (e.g., can change position according to the attractive force). At least some of the plurality of light-emitting elements 500 may be located on the conductive pattern DP. In some embodiments, some of the light-emitting elements 500 may have conductive balls DB positioned on the conductive pattern DP. Because the attractive force caused by the first electromagnetic field EP1 is weakened and applied to other light-emitting elements 500, such as light-emitting elements 500 spaced apart from the conductive pattern DP, their conductive balls DB may not be positioned on the conductive pattern DP. Some of the light-emitting elements 500 may be movable so that they can be positioned in the spaces between the conductive patterns DP, or so that a portion of each of them can be positioned on the conductive pattern DP.

[0118] Here, when the conductive pattern DP has too large a diameter, a plurality of light emitting elements 500 may be simultaneously mounted on one conductive pattern DP. According to an embodiment, the diameter WD of the conductive pattern DP of the base substrate BS (see Figure 11 ) may be smaller than the length WB of the major axis of the light emitting element 500 and the diameter (or width) WA of the minor axis of the light emitting element 500. By forming the diameter WD of the conductive pattern DP to be smaller than the diameter (or width) WA of the minor axis of the light emitting element 500, it is possible to prevent (or substantially prevent) a plurality of light emitting elements 500 from being arranged on the same conductive pattern DP.

[0119] According to some embodiments, the diameter WD of the conductive pattern DP may be greater than the diameter WC of the conductive ball DB of the light emitting element 500 (see FIG. Figure 11 ), so that the light-emitting element 500 can be easily positioned on the conductive pattern DP. When the conductive pattern DP is too small, the first electromagnetic field EP1 generated by the applied first alignment signal may have a weak intensity (e.g., may be weak), and the movement of the light-emitting element 500 may be insufficient (or mismatched). Therefore, the diameter WD of the conductive pattern DP may be larger than the diameter WC of the conductive ball DB of the light-emitting element 500. However, the present disclosure is not limited thereto.

[0120] When the first electromagnetic field EP1 is generated on the conductive pattern DP, an attractive force may be applied to the conductive balls DB of the light-emitting elements 500 dispersed in the ink Ink, and the light-emitting elements 500 may change (e.g., change) their positions on the base substrate BS. However, as described above, not all light-emitting elements 500 in the ink Ink may be placed on the conductive pattern DP. Some of the light-emitting elements 500 may be located in the space between the conductive patterns DP, or may be positioned so that the conductive balls DB of the light-emitting elements 500 are not placed on the conductive pattern DP. According to an embodiment, by adjusting the distance between the conductive patterns DP, when the light-emitting elements 500 are aligned in a subsequent process, the light-emitting elements 500 that are not located on the conductive pattern DP may change (e.g., change) their positions.

[0121] Figures 13 to 15 is a schematic diagram illustrating one operation of a method of aligning a light emitting element according to an embodiment.

[0122] Reference Figures 13 to 15 When at least some of the light-emitting elements 500 are positioned on the conductive pattern DP, the light-emitting elements 500 may be oriented in a single direction (S400). According to an embodiment, oriented the light-emitting elements 500 in a single direction is an operation of determining the orientation of the plurality of light-emitting elements 500, and may include changing the direction of the long axis of the light-emitting elements 500 or the direction of one end of any of the light-emitting elements 500. As an example, oriented the light-emitting elements 500 in a single direction may include applying a second alignment signal to the first alignment electrode ED1 and the second alignment electrode ED2 on the base substrate BS to form a second electromagnetic field EP2 on the base substrate BS, thereby changing the direction of the long axis of the light-emitting elements 500.

[0123] For example, even when the light emitting element 500 is located on the conductive pattern DP, the direction of the long axis of the light emitting element 500 may be randomly oriented. Here, when the second electromagnetic field EP2 is formed on the base substrate BS in one direction, the light emitting element 500 may receive the dielectrophoretic force caused by the second electromagnetic field EP2 and thus may change (e.g., alter) the orientation of the long axis.

[0124] For example, Figure 13As shown in FIG, the first alignment electrode ED1 and the second alignment electrode ED2 may be spaced apart from each other along the second direction DR2 on the base substrate BS. A plurality of conductive patterns DP may be between the first alignment electrode ED1 and the second alignment electrode ED2, and the light-emitting element 500 may be placed or arranged on the conductive patterns DP. When a second alignment signal is applied to the first alignment electrode ED1 and the second alignment electrode ED2, a second electromagnetic field EP2 directed in one direction may be generated above the base substrate BS or between the first alignment electrode ED1 and the second alignment electrode ED2. In an exemplary embodiment, an AC voltage may be applied to the first alignment electrode ED1, and the second alignment electrode ED2 may be grounded. The second electromagnetic field EP2 may be generated in a direction from the first alignment electrode ED1 to the second alignment electrode ED2 (e.g., in the second direction DR2). The second electromagnetic field EP2 may be an electric field and / or a magnetic field generated by the second alignment signal, but the present disclosure is not limited thereto.

[0125] The light emitting element 500 may receive the dielectrophoretic force due to the second electromagnetic field EP2 and thus may change (e.g., alter) its orientation. Similar to the second electromagnetic field EP2 directed in one direction, the light emitting element 500 may also be directed to point in the same direction. According to an embodiment, the light emitting element 500 may have a magnetic force DM formed in the same direction as the direction of the long axis (see FIG. Figure 14 ). For example, the first electrode unit 560 and the second electrode unit 570 of each of the light-emitting elements 500 can be spaced apart from each other along the direction of the long axis, and a magnetic force DM can be formed between the first electrode unit 560 and the second electrode unit 570. As an example, the lower substrate 501 of the light-emitting element 500 may include a material having a magnetic substance, and a magnetic force DM such as ferromagnetism and / or paramagnetism can be distributed to the lower substrate 501. Therefore, a magnetic force DM pointing in the direction of the long axis or in the direction in which the first electrode unit 560 and the second electrode unit 570 are spaced apart from each other can be formed. In some embodiments, the light-emitting element 500 can receive a dielectrophoretic force so that the direction of the long axis is the same as the direction of the second electromagnetic field EP2 (e.g., becomes the same as the direction of the second electromagnetic field EP2). For example, according to an embodiment, determining the orientation of the light-emitting element 500 in the method of aligning the light-emitting element 500 may include orienting the light-emitting element 500 so that the direction of the long axis and the direction of the second electromagnetic field EP2 are the same as each other.

[0126] like Figure 15 As shown in FIG, the magnetic force DM pointing in one direction may be formed on the first electrode unit 560 or the first electrode layer 561 (see FIG. Figure 9 ) and the second electrode unit 570 or the second electrode layer 571 (see Figure 9) between them. This dipole moment can be formed by doping the first electrode layer 561 and the second electrode layer 571 of the light-emitting element 500 with impurities of different conductivity types (e.g., p-type or n-type). However, the present disclosure is not limited thereto. Therefore, as long as the first electrode unit 560 and the second electrode unit 570 include conductive materials and a dipole moment can be formed therebetween, the method of forming the dipole moment is not particularly limited.

[0127] As an example, a magnetic force DM pointing in the direction from the first electrode unit 560 to the second electrode unit 570 (the direction is the same as the long axis direction) can be formed in the light-emitting element 500. In this case, the light-emitting element 500 can receive the dielectrophoretic force so that the direction of the magnetic force DM is the same as the direction of the second electromagnetic field EP2 (becomes the same as the direction of the second electromagnetic field EP2). The light-emitting elements 500 (each of which has a shape extending in one direction) can be aligned with each other on the conductive pattern DP by changing (e.g., altering) their respective positions and orientations due to the dielectrophoretic force.

[0128] In some embodiments, when an alignment signal is applied to the conductive pattern DP and the conductive ball DB is placed on the conductive pattern DP, the light emitting element 500 may be rotated so that only the orientation is changed while maintaining the position. To this end, according to an embodiment, determining the orientation of the light emitting element 500 may include applying a third alignment signal to the conductive pattern DP and generating a third electromagnetic field EP3 (see FIG. 1 ) by the third alignment signal. Figure 15 ) transmits an attractive force to the conductive ball DB. The third alignment signal may have a greater strength than the first alignment signal, and the third electromagnetic field EP3 may transmit an attractive force stronger than the first electromagnetic field EP1. Therefore, when the conductive ball DB is placed on the conductive pattern DP, the light emitting element 500 may change (e.g., alter) its orientation only due to the second electromagnetic field EP2, while the position of the conductive ball DB does not change. Figure 14 As shown in , some light emitting elements 500 may have a conductive ball DB whose position does not need to be varied (e.g., changed), and these light emitting elements 500 may be rotated around the conductive ball DB so that only the orientation of the light emitting element 500 can be varied (e.g., changed). In some embodiments, the light emitting element 500 may be oriented such that the second direction DR2, which is the direction in which the second electromagnetic field EP2 is applied, is the same as the direction of the magnetic force DM when the light emitting element 500 is positioned on the conductive pattern DP.

[0129] In some embodiments, some of the light-emitting elements 500 may have conductive balls DB that are not positioned on the conductive pattern DP but are partially positioned on the conductive pattern DP or in the spaces between the conductive patterns DP. Due to the third electromagnetic field EP3 formed on the conductive pattern DP, the light-emitting elements 500 partially positioned on the conductive pattern DP may receive a strong attractive force and then move so that the conductive balls DB are positioned on the conductive pattern DP. Simultaneously (or in parallel), the light-emitting elements 500 may receive a dielectrophoretic force caused by the second electromagnetic field EP2, and thus some of the light-emitting elements 500 may be oriented while positioned on the conductive pattern DP.

[0130] Despite receiving an attractive force due to the third electromagnetic field EP3, some light-emitting elements 500 may still be located in the spaces between the conductive patterns DP, and thus may have conductive balls DB that are not positioned on the conductive patterns DP. In this case, due to the second electromagnetic field EP2, the orientations of these light-emitting elements 500 may change (e.g., shift) while their positions continuously (or simultaneously) change (e.g., shift). According to embodiments, by adjusting the distances between the conductive patterns DP to be regular (e.g., substantially regular), the risk of light-emitting elements 500 only changing (e.g., shifting) in orientation without being positioned on the conductive patterns DP can be prevented or reduced.

[0131] According to an embodiment, the distance between the conductive patterns DP may include distances WP1 and WP2 that separate the conductive patterns DP from each other in corresponding directions. The first distance WP1 in a direction intersecting (e.g., perpendicular) to the direction of the second electromagnetic field EP2 may be shorter than the length WB of the major axis of the light-emitting element 500. For example, the conductive patterns DP may be spaced apart from each other in the first direction DR1 and the second direction DR2. Some of the conductive patterns DP may be spaced apart from each other by the first distance WP1 (by the first distance WP1) in the first direction DR1, and other conductive patterns DP may be spaced apart from each other by the second distance WP2 (by the second distance WP2) in the second direction DR2. As described above, when the second electromagnetic field EP2 is generated in the second direction DR2, the first distance WP1 separating the conductive patterns DP from each other in the first direction DR1 may be shorter than the length WB of the major axis of the light-emitting element 500.

[0132] When any light-emitting element 500 receives a dielectrophoretic force due to the second electromagnetic field EP2 while its conductive ball DB is positioned on the conductive pattern DP, the light-emitting element 500 may rotate about the conductive pattern DP, causing the orientation of the light-emitting element 500 to change. Here, another light-emitting element 500 located between one conductive pattern DP and another conductive pattern DP spaced apart from the first conductive pattern DP in the first direction DR1 may physically contact the rotating light-emitting element 500, and thus the position and orientation of the other light-emitting element 500 may change (e.g., be altered). For example, a light-emitting element 500 located between conductive patterns DP may collide with another light-emitting element 500, causing the position and orientation of the light-emitting element 500 between the conductive patterns DP to change, and thus the light-emitting element 500 may move into an area affected by the third electromagnetic field EP3 generated on the conductive pattern DP. In this case, the conductive ball DB of the corresponding light-emitting element 500 may receive an attractive force due to the third electromagnetic field EP3 generated on the corresponding conductive pattern DP. Consequently, the conductive ball DB of the light-emitting element 500 may be positioned on the corresponding conductive pattern DP.

[0133] When the distance between the conductive patterns DP is too large, there may be light-emitting elements 500 that are not in physical contact with the light-emitting elements 500 rotating around the conductive patterns DP. In this case, the light-emitting elements 500 may remain unplaced on the conductive patterns DP (for example, they may remain between the conductive patterns DP). To prevent or reduce the risk of this, the distance between the conductive patterns DP can be adjusted based on the length WB of the major axis of the light-emitting elements 500, the diameter (or width) WA of the minor axis of the light-emitting elements 500, and the like.

[0134] In an exemplary embodiment, the conductive patterns DP are spaced apart from each other by a first distance WP1 in the first direction DR1 that is greater than the diameter (or width) WA of the minor axis of the light emitting element 500, and may be less than twice the diameter (or width) WA of the minor axis. In some embodiments, the conductive patterns DP are spaced apart from each other by a second distance WP2 in the second direction DR2 that is greater than the length WB of the major axis of the light emitting element 500, and may be less than twice the length WB of the major axis.

[0135] As described above, the magnetic force DM can be formed in the same direction as the long axis of the light-emitting element 500, and thus the light-emitting element 500 can be oriented in the direction of the second electromagnetic field EP2. In a single light-emitting element 500, a long axis length WB pointing in the same direction as the second electromagnetic field EP2 and a short axis diameter (or width) WA perpendicular to the long axis can be defined. The plurality of conductive patterns DP can be spaced apart from each other by a second distance WP2 in the second direction DR2 (which is the direction of the second electromagnetic field EP2) and can be spaced apart from each other by a first distance WP1 in the first direction DR1 (which intersects (e.g., is perpendicular) to the direction of the second electromagnetic field EP2). The first distance WP1 and the second distance WP2 between the conductive patterns DP can be adjusted to within the above-described ranges, respectively, based on the short axis diameter (or width) WA and the long axis length WB of the light-emitting element 500. Therefore, when aligning the light-emitting elements 500 with the conductive balls DB positioned on the conductive patterns DP, the light-emitting elements 500 located between the conductive patterns DP may also change (e.g., alter) their positions and orientations due to physical contact with the positioned light-emitting elements 500 and thus may also be positioned on the conductive patterns DP. Thus, one light-emitting element 500 may be positioned on each conductive pattern DP, and the plurality of light-emitting elements 500 may be aligned such that the orientations (i.e., the directions of the major axes) of the light-emitting elements 500 are consistent (e.g., substantially consistent).

[0136] Figure 16 is a plan view illustrating a base substrate on which a light emitting element is aligned according to an embodiment.

[0137] Reference Figure 16 , the plurality of light emitting elements 500 on the base substrate BS may be spaced apart from each other at a uniform (e.g., substantially uniform) distance and may be aligned such that the long axes of the light emitting elements 500 are oriented in the same direction. As described above, the method of aligning the light emitting elements 500 according to the embodiment may include aligning (e.g., positioning) the light emitting elements 500 on the conductive patterns DP on the base substrate BS using the conductive balls DB and the conductive patterns DP of the light emitting elements 500, and determining (e.g., changing) the orientation of the light emitting elements 500.

[0138] Thus, the plurality of light-emitting elements 500 can be evenly (e.g., substantially evenly) spaced apart from one another according to the conductive pattern DP, and their major axis orientations can be uniformly (e.g., substantially uniformly) aligned. Similar to the conductive pattern DP, the light-emitting elements 500 can be spaced apart from one another and oriented in the first direction DR1 and the second direction DR2. The conductive patterns DP can be spaced apart from one another by (or by) a first distance WP1 and a second distance WP2, and the first distance WP1 and the second distance WP2 can have a set or specific relationship with the diameter (or width) WA and the length WB of the major axis of the light-emitting elements 500. Similarly, the distances between the light-emitting elements 500 in the first direction DR1 and the second direction DR2 can have a set or specific relationship with the diameter (or width) WA and the length WB of the major axis of the light-emitting elements 500. As an example, the distances between the light-emitting elements 500 in the first direction DR1 can each be shorter than the length WB of the major axis of the light-emitting elements 500. Furthermore, the distances between the light-emitting elements 500 in the second direction DR2 can each be shorter than the length WB of the major axis of the light-emitting elements 500. However, the present disclosure is not limited to this.

[0139] Subsequently, by removing the ink Ink ejected onto the base substrate BS, the light emitting element 500 can be aligned on the base substrate BS. The method of removing the ink Ink may include a drying process using heat treatment, a drying process using light irradiation, etc., and is not particularly limited.

[0140] As described above, the display device 10 including the plurality of light emitting elements 500 can be manufactured by a process of transferring the light emitting elements 500 aligned on the base substrate BS to the target substrate SUB. Figure 4 and Figure 16 As shown in FIG, the light emitting element 500 can be aligned on the base substrate BS, and the areas corresponding to the pixels PX and sub-pixels PXn of the display device 10 can be defined on the target substrate SUB. The display device 10 can be formed by using a transfer device TD (see FIG. Figure 4 ) The light emitting element 500 is transferred from the base substrate BS to the target substrate SUB to be manufactured. The display device 10 manufactured by the above method will be described below with reference to other drawings.

[0141] Figure 17 is a cross-sectional view illustrating one sub-pixel of a display device according to an embodiment.

[0142] Reference Figure 2 、 Figure 3 and Figure 17, the display device 10 may include a first substrate 101, a plurality of semiconductor layers, a plurality of conductive layers, a plurality of insulating layers, and a light emitting element 500 on the first substrate 101. The plurality of semiconductor layers and the plurality of conductive layers may form circuit elements of each sub-pixel PXn, and another conductive layer and the light emitting element 500 may form a light emitting diode EL of each sub-pixel PXn. Figure 17 In FIG. 1 , only the light emitting element 500 and the driving transistor DT are shown above the first substrate 101, but the present disclosure is not limited thereto. The display device 10 may further include additional components, such as a scanning transistor SCT, a sensing transistor SST, etc. In addition, for ease of description, in FIG. Figure 17 Schematically shown in FIG 5 . However, only the driving transistor DT shown on the first substrate 101 will be described in more detail below.

[0143] The first substrate 101 may be an insulating substrate. The first substrate 101 may be made of an insulating material such as glass, quartz, and / or polymer resin. In addition, the first substrate 101 may be a rigid substrate, or a flexible substrate that is bendable, foldable, and / or rollable.

[0144] In some embodiments, a light blocking layer and a buffer layer may be further disposed on the first substrate 101. The light blocking layer may be formed of an opaque metal material that blocks or reduces light transmission, thereby preventing or reducing light from being incident on the active material layer ACT of the driving transistor DT.

[0145] In addition, in addition to the light blocking layer, a buffer layer may be arranged on the entire first substrate 101. The buffer layer may perform a surface planarization function while protecting the driving transistor DT of the pixel PX from moisture that penetrates through the first substrate 101 (which is susceptible to moisture penetration). The buffer layer may include a plurality of inorganic layers stacked alternately. For example, the buffer layer may include a plurality of layers in which one or more inorganic layers are alternately stacked, each of the inorganic layers including a silicon oxide SiO x , silicon nitride SiN x and one of silicon oxynitride SiON.

[0146] The active material layer ACT of the driving transistor DT may be disposed on the first substrate 101 or the buffer layer. In an exemplary embodiment, the active material layer ACT may include polycrystalline silicon, single crystal silicon, an oxide semiconductor, or the like. Polycrystalline silicon may be formed by crystallizing amorphous silicon. Examples of such crystallization methods may include a rapid thermal annealing (RTA) method, a solid phase crystallization (SPC) method, an excimer laser annealing (ELA) method, a metal induced crystallization (MILC) method, and a sequential lateral solidification (SLS) method, but the present disclosure is not limited thereto. When the active material layer ACT includes polycrystalline silicon, the active material layer ACT may include a first doped region ACTa, a second doped region ACTb, and a first channel region ACTc. The first channel region ACTc may be between the first doped region ACTa and the second doped region ACTb. The first doped region ACTa and the second doped region ACTb may be regions obtained by doping some regions of the active material layer ACT with impurities.

[0147] In an exemplary embodiment, the active material layer ACT may include an oxide semiconductor. In this case, each of the doped regions of the active material layer ACT may be a conductive region. The oxide semiconductor may be an oxide semiconductor including indium (In). In some embodiments, the oxide semiconductor may be indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium oxide (IGO), indium zinc tin oxide (IZTO), indium gallium tin oxide (IGTO), indium gallium zinc tin oxide (IGZTO), etc. However, the present disclosure is not limited thereto.

[0148] The first gate insulating layer 102 is located on the semiconductor layer (for example, on the active material layer ACT) and the buffer layer. The first gate insulating layer 102 may be on the semiconductor layer, and may be on the first substrate 101 or the buffer layer. The first gate insulating layer 102 may serve as a gate insulating layer of the driving transistor DT. The first gate insulating layer 102 may be made of an inorganic material (for example, silicon oxide (SiO x ) or silicon nitride (SiN x )) is formed, or can be formed by a stacked structure thereof.

[0149] The first gate conductive layer is located on the first gate insulating layer 102. The first gate conductive layer may include a first gate electrode DT_G of the drive transistor DT. The first gate electrode DT_G may overlap at least a portion of the active material layer ACT. For example, the first gate electrode DT_G may overlap the first channel region ACTc of the active material layer ACT in the thickness direction.

[0150] The first gate conductive layer may include a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and alloys thereof. However, the present disclosure is not limited thereto.

[0151] The first protective layer 103 is located on the first gate conductive layer. The first protective layer 103 can cover and protect the first gate conductive layer. The first protective layer 103 can be made of an inorganic material (e.g., silicon oxide (SiO x ) or silicon nitride (SiN x )) is formed, or can be formed by a stacked structure thereof.

[0152] The first interlayer insulating layer 105 is located on the first protective layer 103. The first interlayer insulating layer 105 may be used as an insulating film between the first protective layer 103 and other layers on the first interlayer insulating layer 105. The first interlayer insulating layer 105 may be made of an inorganic material (e.g., silicon oxide (SiO x ) or silicon nitride (SiN x )) is formed, or can be formed by a stacked structure thereof.

[0153] The first data conductive layer is positioned on the first interlayer insulating layer 105. The first data conductive layer may include a first source / drain electrode DT_S and a second source / drain electrode DT_D of the driving transistor DT.

[0154] The first source / drain electrode DT_S and the second source / drain electrode DT_D of the driving transistor DT can respectively contact (e.g., physically contact) the first doped region ACTa and the second doped region ACTb of the active material layer ACT through contact holes passing through the first interlayer insulating layer 105, the first protective layer 103, and the first gate insulating layer 102. In some embodiments, the first source / drain electrode DT_S of the driving transistor DT can be electrically coupled to the light blocking layer through another contact hole. When any one of the first source / drain electrode DT_S and the second source / drain electrode DT_D of the driving transistor DT is a source electrode, the other can be a drain electrode. However, the present disclosure is not limited thereto. When any one of the first source / drain electrode DT_S and the second source / drain electrode DT_D is a drain electrode, the other can be a source electrode.

[0155] The first data conductive layer may include a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and alloys thereof. However, the present disclosure is not limited thereto.

[0156] The second interlayer insulating layer 107 may be on the first data conductive layer. The second interlayer insulating layer 107 may be disposed on the entire first interlayer insulating layer 105, while covering the first data conductive layer and protecting the first data conductive layer. The second interlayer insulating layer 107 may be made of an inorganic material (e.g., silicon oxide (SiO x ) or silicon nitride (SiN x )) is formed, or can be formed by a stacked structure thereof.

[0157] The second data conductive layer is on the second interlayer insulating layer 107. The second data conductive layer may include a first conductive line SD1. In some embodiments, a first voltage line VSL for applying a low-level voltage (first power supply voltage) to be supplied to a common electrode 220, which will be described in more detail below, and a second voltage line VDL for applying a high-level voltage (second power supply voltage) to be supplied to the driving transistor DT may also be provided in the second data conductive layer.

[0158] The first conductive line SD1 may be electrically coupled to the first source / drain electrode DT_S of the driving transistor DT through a contact hole formed in the second interlayer insulating layer 107. The first conductive line SD1 may contact the pixel electrode 210, which will be described in more detail below, and the driving transistor DT may transmit a second power supply voltage applied from the second voltage line VDL to the pixel electrode 210 through the first conductive line SD1.

[0159] The second data conductive layer may include a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and alloys thereof. However, the present disclosure is not limited thereto.

[0160] The first planarization layer 109 is located on the second data conductive layer. The first planarization layer 109 may include an organic insulating material and perform a surface planarization function.

[0161] A first electrode and a second electrode are provided on the first planarization layer 109. The first electrode may be a pixel electrode 210, and the second electrode may be a common electrode 220. The pixel electrode 210 and the common electrode 220 may be spaced apart from each other. The pixel electrode 210 may contact the first conductive line SD1 via a contact hole formed through the first planarization layer 109 to expose the first conductive line SD1. In some embodiments, the common electrode 220 may contact the first voltage line VSL via the contact hole formed through the first planarization layer 109. Therefore, a first power supply voltage may be applied to the common electrode 220, and a second power supply voltage may be applied to the pixel electrode 210 via the drive transistor DT and the first conductive line SD1. In an exemplary embodiment, a pixel electrode 210 may be provided separately for each sub-pixel PXn, and the common electrode 220 may be an electrode commonly coupled to the sub-pixels PXn. The pixel electrode 210 may be an anode electrode of the light-emitting diode EL, and the common electrode 220 may be a cathode electrode of the light-emitting diode EL. However, the present disclosure is not limited thereto, and the reverse is also possible.

[0162] The light-emitting element 500 may be on the pixel electrode 210 and the common electrode 220. For example, the first electrode unit 560 of the light-emitting element 500 may be on the pixel electrode 210, and the second electrode unit 570 of the light-emitting element 500 may be on the common electrode 220. According to an embodiment, the light-emitting element 500 may include a conductive ball DB on the first electrode unit 560 or the second electrode unit 570, and the conductive ball DB may be in contact with (e.g., physically in contact with) the pixel electrode 210 or the common electrode 220. Figure 17 , the conductive ball DB is shown to be on the first electrode unit 560, and the conductive ball DB is in contact with the pixel electrode 210. However, the present disclosure is not limited thereto. When the conductive ball DB is on the second electrode unit 570, the conductive ball DB may be in contact with the common electrode 220, and the first electrode layer 561 (see FIG. 5 ) of the first electrode unit 560 may be in contact with the common electrode 220. Figure 9 ) may contact the pixel electrode 210. Therefore, the first electrode unit 560 of the light emitting element 500 may be electrically coupled to the first electrode or the pixel electrode 210, and the second electrode unit 570 of the light emitting element 500 may be electrically coupled to the second electrode or the common electrode 220.

[0163] The display device 10 can be manufactured by transferring the aligned light-emitting element 500 onto the target substrate SUB using the method of aligning the light-emitting element 500 of the present embodiment. Here, in order to uniformly (e.g., substantially uniformly) align the light-emitting element 500, the conductive pattern DP and the conductive ball DB can be used for the method of aligning the light-emitting element 500 according to the embodiment. The conductive ball DB of the light-emitting element 500 can remain on the light-emitting element 500 transferred to the target substrate SUB. In addition, according to the embodiment, the conductive pattern DP can be on at least one of the first electrode 210 and the second electrode 220. As an example, the conductive pattern DP can be formed by a process for metal deposition and patterning during the process (action) of forming the first electrode 210 and the second electrode 220. However, the present disclosure is not limited thereto.

[0164] When the conductive pattern DP is on the first electrode 210 or the second electrode 220, the light-emitting element 500 can be arranged so that the conductive ball DB corresponds to the conductive pattern DP during the process of arranging the light-emitting element 500. Therefore, according to an embodiment, using the method of aligning the light-emitting element 500 of this embodiment, a plurality of light-emitting elements 500 can be positioned uniformly (e.g., substantially uniformly) between the first electrode 210 and the second electrode 220. In addition, as described above, the conductive ball DB and the conductive pattern DP include a conductive material. Therefore, even when the conductive ball DB is between the pixel electrode 210 or the common electrode 220 of the light-emitting element 500 and the electrode units 560 and 570, the light-emitting element 500 can receive an electrical signal from the pixel electrode 210 and the common electrode 220.

[0165] A method of aligning the light emitting element 500 according to another embodiment will be described below.

[0166] Figure 18 is a plan view showing a base substrate on which a light emitting element is aligned according to another embodiment.

[0167] Reference Figure 18 , the method of aligning the light emitting element 500_1 according to the embodiment may include aligning light emitting elements 500a_1, 500b_1 and 500c_1 of different types (or kinds) on the same base substrate BS. Figure 4 The embodiment of FIG. 5 may differ in that the light emitting elements 500_1 may be different and may be aligned separately. The following description will focus on this difference, and redundant descriptions of the same elements will not be provided.

[0168] exist Figure 18In an embodiment, the light-emitting element 500_1 may include different light-emitting elements, such as a first light-emitting element 500a_1, a second light-emitting element 500b_1, and a third light-emitting element 500c_1. The light-emitting element 500_1 may emit light of different colors depending on the type (e.g., material) of the active layer 530. Depending on the embodiment, the first light-emitting element 500a_1 may emit light of a first color, the second light-emitting element 500b_1 may emit light of a second color, and the third light-emitting element 500c_1 may emit light of a third color. The first color may be blue, the second color may be green, and the third color may be red.

[0169] like Figure 2 and Figure 18 As shown in , when multiple light-emitting elements 500_1 emit light of different colors, the display device 10 including different light-emitting elements 500_1 needs to arrange the light-emitting elements 500_1 in predetermined (or set) pixels PX or sub-pixels PXn. For example, when any pixel PX includes a first sub-pixel PX1 that displays light of a first color, a second sub-pixel PX2 that displays light of a second color, and a third sub-pixel PX3 that displays light of a third color, the first light-emitting element 500a_1, the second light-emitting element 500b_1, and the third light-emitting element 500c_1 need to be arranged in the first sub-pixel PX1, the second sub-pixel PX2, and the third sub-pixel PX3, respectively. Similarly, when aligning different light-emitting elements 500_1, specific light-emitting elements 500_1 need to be placed and aligned on corresponding conductive patterns DP. In the method of aligning light-emitting elements 500_1 according to an embodiment, the conductive pattern DP on the base substrate BS may include different conductive patterns DP1, DP2, and DP3. In the operation of positioning or disposing the light emitting element 500_1 on the conductive pattern DP, different light emitting elements 500a_1, 500b_1, and 500c_1 may be positioned or disposed on different conductive patterns DP1, DP2, and DP3.

[0170] Figures 19 to 21 is a schematic diagram illustrating some operations of a method of aligning a light emitting element according to another embodiment.

[0171] Reference Figures 19 to 21, the base substrate BS may include a plurality of conductive patterns DP1, DP2, and DP3, and the first alignment signal may be applied separately to the plurality of conductive patterns DP1, DP2, and DP3. The plurality of first conductive patterns DP1, the plurality of second conductive patterns DP2, and the plurality of third conductive patterns DP3 may be spaced apart from each other in the second direction DR2 (for example, the plurality of first conductive patterns DP1 may be spaced apart from each other in the second direction DR2, the plurality of second conductive patterns DP2 may be spaced apart from each other in the second direction DR2, and the plurality of third conductive patterns DP3 may be spaced apart from each other in the second direction DR2). The first conductive pattern DP1 and the second conductive pattern DP2 may be spaced apart from each other in the first direction DR1, and the second conductive pattern DP2 and the third conductive pattern DP3 may be spaced apart from each other in the first direction DR1. For example, the same conductive patterns among the conductive patterns DP1, DP2, and DP3 may be spaced apart from each other in the second direction DR2 to form a linear pattern on the base substrate BS. Different conductive patterns DP1, DP2, and DP3 may be spaced apart from each other in the first direction DR1 and may be repeated alternately.

[0172] The base substrate BS may have lines for applying the first and third alignment signals to the conductive patterns DP1, DP2, and DP3. Figure 10 Depending on the embodiment, different conductive patterns (e.g., the first conductive pattern DP1, the second conductive pattern DP2, and the third conductive pattern DP3) can be electrically connected to different lines, and alignment signals can be applied to the conductive patterns separately. Therefore, the method of aligning the light-emitting element 500 according to the embodiment can include individually aligning different light-emitting elements 500.

[0173] For example, Figure 19 As shown in FIG, the ink Ink in which the first light emitting elements 500a_2 are dispersed is ejected onto the base substrate BS, and the first alignment signal is applied only to the first conductive pattern DP1. Figure 8 and Figure 10 Similarly, the conductive ball DB of the first light emitting element 500a_2 ejected onto the base substrate BS receives an attractive force from the first electromagnetic field EP1 generated by the first conductive pattern DP1, and thus the first light emitting element 500a_2 may be seated on the first conductive pattern DP1.

[0174] Then, if Figure 20As shown in FIG, ink Ink having second light-emitting elements 500b_2 dispersed therein is ejected onto a base substrate BS, a first alignment signal is applied to the second conductive pattern DP2, and a third alignment signal is applied to the first conductive pattern DP1. Consequently, the conductive balls DB of the second light-emitting elements 500b_2 can receive an attractive force from the first electromagnetic field EP1 generated on the second conductive pattern DP2, and thus the second light-emitting elements 500b_2 can be positioned on the second conductive pattern DP2. Simultaneously, a third alignment signal having a greater intensity than the first alignment signal is applied to the first conductive pattern DP1, thereby generating a third electromagnetic field EP3 having a greater intensity on the first conductive pattern DP1. Therefore, even when the first electromagnetic field EP1 is generated in the second conductive pattern DP2, the first light-emitting elements 500a_2 positioned on the first conductive pattern DP1 can remain positioned on the first conductive pattern DP1 without changing their positions. Furthermore, because no alignment signal is applied to the third conductive pattern DP3, no light-emitting elements are positioned on the third conductive pattern DP3.

[0175] Then, if Figure 21 As shown in FIG, ink Ink having third light-emitting elements 500c_2 dispersed therein is ejected onto base substrate BS, a first alignment signal is applied to third conductive pattern DP3, and a third alignment signal is applied to first conductive pattern DP1 and second conductive pattern DP2. As a result, first light-emitting element 500a_2 can be positioned or located on first conductive pattern DP1, second light-emitting element 500b_2 can be positioned or located on second conductive pattern DP2, and third light-emitting element 500c_2 can be positioned or located on third conductive pattern DP3. The description is the same as above.

[0176] Afterwards, with Figure 13 Similarly, alignment electrodes ED1 and ED2 provided on the base substrate BS can be used to generate a second electromagnetic field EP2 to align the directions of the first light-emitting element 500a_2, the second light-emitting element 500b_2, and the third light-emitting element 500c_2. According to an embodiment, conductive patterns DP1, DP2, and DP3, to which alignment signals can be applied individually, can be used to align different light-emitting elements at desired positions.

[0177] In some embodiments, the conductive pattern DP on the base substrate BS may correspond to the shape of an area defined on the target substrate SUB to which the light-emitting element 500 will be transferred. For example, when the light-emitting element 500 is arranged on the target substrate SUB in an oblique direction rather than in the first direction DR1 and the second direction DR2, the conductive pattern DP on the base substrate BS may be arranged in a corresponding structure.

[0178] Figure 22is a plan view showing a base substrate on which a light emitting element is aligned according to another embodiment.

[0179] Reference Figure 22 According to an embodiment, the conductive patterns DP of the base substrate BS_3 may not necessarily be arranged in a first direction and a second direction perpendicular to the first direction. For example, a plurality of conductive patterns DP may be spaced apart from each other in one direction and another direction intersecting the one direction but not perpendicular to the one direction. Therefore, the light emitting elements 500 aligned on the conductive patterns DP may be aligned in one direction and another direction not perpendicular to the one direction but intersecting the one direction. In this case, the method for aligning the light emitting elements 500 according to the embodiment may be used to manufacture a light emitting device having the same Figure 2 The display device 10 is different from the display device 10 in terms of the arrangement of the pixels PX and the arrangement of the sub-pixels PXn. The description of the various elements is the same as that provided above, and thus a redundant description thereof will not be provided.

[0180] The method of aligning light-emitting elements according to an embodiment may include positioning or placing the light-emitting elements on the conductive pattern and then orienting the light-emitting elements in one direction. Thus, the light-emitting elements may be formed on the substrate at a uniform (e.g., substantially uniform) distance and oriented in a specific direction.

[0181] Furthermore, according to an embodiment, a display device including a plurality of pixels may be manufactured using a method of aligning a light emitting element, and in the display device, a light emitting element may be located at a precise position for each pixel.

[0182] As used herein, the terms "use," "using," and "used" may be considered synonymous with the terms "utilize," "utilizing," and "utilized," respectively.

[0183] Additionally, the terms "substantially," "about," and similar terms are used as terms of approximation, not terms of degree, and are intended to allow for the inherent deviations in measurements or calculations that would be recognized by one of ordinary skill in the art.

[0184] In addition, any numerical range described herein is intended to include all subranges with the same numerical precision contained within the described range. For example, the range of "1.0 to 10.0" is intended to include all subranges between the described minimum value of 1.0 and the described maximum value of 10.0 (and including this number), that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification, including the claims, to clearly describe any subranges contained within the range explicitly described herein.

[0185] At the end of the detailed description, those skilled in the art will appreciate that many changes and modifications may be made to the exemplary embodiments without departing substantially from the principles of the present disclosure. Therefore, the disclosed embodiments are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A method for aligning a light emitting element, the method comprising: providing a base substrate and a plurality of conductive patterns on the base substrate, the plurality of conductive patterns being spaced apart from each other; ejecting ink in which a plurality of light emitting elements are dispersed onto the base substrate, and positioning the plurality of light emitting elements on the plurality of conductive patterns; as well as orienting the plurality of light emitting elements by orienting one end of each of the plurality of light emitting elements in a first direction, The light-emitting element includes a first electrode unit and a second electrode unit respectively located at both ends of the light-emitting element, and also includes a conductive ball on the first electrode unit and in direct contact with the first electrode unit, and the second electrode unit does not contact any conductive ball.

2. The method according to claim 1, wherein Positioning the plurality of light emitting elements comprises: applying a first alignment signal to the plurality of conductive patterns to generate a first electromagnetic field on the plurality of conductive patterns, and At least a portion of the plurality of light emitting elements is positioned on the plurality of conductive patterns.

3. The method according to claim 2, wherein: The first electromagnetic field exerts an attractive force on the conductive ball, and Positioning the plurality of light emitting elements includes placing the conductive balls of the at least a portion of the plurality of light emitting elements on the plurality of conductive patterns.

4. The method according to claim 2, wherein: further arranging a first alignment electrode and a second alignment electrode on the base substrate, the first alignment electrode and the second alignment electrode being spaced apart from each other in the first direction, and Orienting the plurality of light emitting elements includes applying a second alignment signal to the first alignment electrode and the second alignment electrode to generate a second electromagnetic field on the base substrate and change the position and / or orientation of the plurality of light emitting elements.

5. The method according to claim 4, wherein Orienting the plurality of light emitting elements includes applying a third alignment signal to the plurality of conductive patterns to generate a third electromagnetic field that is stronger than the first electromagnetic field.

6. The method according to claim 4, wherein: In orienting the plurality of light emitting elements, One end of each of the plurality of light emitting elements positioned on the plurality of conductive patterns is oriented in the first direction, and The plurality of light emitting elements not positioned or partially positioned on the plurality of conductive patterns are moved and placed on the plurality of conductive patterns, and one end of each of the plurality of light emitting elements moved and placed on the plurality of conductive patterns is oriented in the first direction.

7. The method according to claim 1, wherein Each of the plurality of light emitting elements has a major axis extending in one direction and is oriented such that the major axis is in the first direction.

8. The method according to claim 7, wherein: A diameter of each of the plurality of light emitting elements is larger than a diameter of each of the plurality of conductive patterns.

9. The method according to claim 7, wherein: The plurality of conductive patterns are spaced apart from each other in the first direction and in a second direction crossing the first direction, The first distance is a distance between the plurality of conductive patterns spaced apart from each other in the first direction, and The first distance is longer than the length of the major axis of each of the plurality of light emitting elements.

10. The method according to claim 9, wherein: The second distance is a distance between the plurality of conductive patterns spaced apart from each other in the second direction, and The second distance is shorter than the length of the major axis of each of the plurality of light emitting elements and longer than a diameter of each of the plurality of light emitting elements.

11. The method according to claim 7, wherein: The plurality of light emitting elements include a first semiconductor layer, a second semiconductor layer, and an active layer located between the first semiconductor layer and the second semiconductor layer, and The first semiconductor layer, the active layer, and the second semiconductor layer are stacked in another direction perpendicular to the one direction in which the plurality of light emitting elements extend.

12. The method according to claim 1, wherein The plurality of conductive patterns include a plurality of first conductive patterns spaced apart from each other in the first direction and a plurality of second conductive patterns spaced apart from each other in the first direction, and The plurality of second conductive patterns are spaced apart from the plurality of first conductive patterns in a second direction crossing the first direction.

13. The method according to claim 12, wherein: The plurality of light emitting elements include a first light emitting element and a second light emitting element, and In positioning the plurality of light emitting elements, generating a third electromagnetic field on the plurality of first conductive patterns, and positioning the first light emitting element on the plurality of first conductive patterns; and A first electromagnetic field is generated on the plurality of second conductive patterns, and the second light emitting element is positioned on the plurality of second conductive patterns.

14. A method for manufacturing a display device, the method comprising: providing a base substrate and a plurality of conductive patterns on the base substrate, the plurality of conductive patterns being spaced apart from each other; ejecting ink having a plurality of light-emitting elements dispersed therein onto the base substrate, wherein each of the plurality of light-emitting elements has a shape extending in one direction and includes a first electrode unit and a second electrode unit respectively located at both ends of the light-emitting element, and further includes a conductive ball on and in direct contact with the first electrode unit, and the second electrode unit does not contact any conductive ball; generating a first electromagnetic field on the plurality of conductive patterns, and positioning the plurality of light emitting elements on the plurality of conductive patterns; generating a second electromagnetic field on the base substrate in a first direction and orienting the plurality of light emitting elements; as well as The plurality of light emitting elements are transferred onto a substrate.

15. The method according to claim 14, wherein The first electromagnetic field exerts an attractive force on the conductive ball, and Positioning the plurality of light emitting elements includes placing the conductive balls on the plurality of conductive patterns.

16. The method according to claim 15, wherein Orienting the plurality of light emitting elements includes rotating the plurality of light emitting elements by the second electromagnetic field so that the one direction in which each of the plurality of light emitting elements extends is parallel to the first direction.

17. The method according to claim 14, wherein: The plurality of light emitting elements are spaced apart from each other in the first direction and a second direction crossing the first direction, and A length of each of the plurality of light emitting elements in the one direction is longer than a distance between adjacent light emitting elements among the plurality of light emitting elements in the second direction.

18. The method according to claim 17, wherein A distance between adjacent light emitting elements among the plurality of light emitting elements in the first direction is shorter than a length of a major axis of each of the plurality of light emitting elements.

19. Display devices, including: a first substrate; a semiconductor layer on the first substrate, wherein the semiconductor layer includes an active material layer of a driving transistor; a gate insulating layer on the semiconductor layer; a first gate conductive layer, on the gate insulating layer, wherein the first gate conductive layer includes a gate electrode of the driving transistor; a first interlayer insulating layer on the first gate conductive layer; a first data conductive layer, on the first interlayer insulating layer; a second interlayer insulating layer on the first data conductive layer; a second data conductive layer on the second interlayer insulating layer, wherein the second data conductive layer includes a first conductive line connected to the first data conductive layer; a first planarization layer on the second data conductive layer; a first electrode and a second electrode on the first planarization layer and spaced apart from each other; as well as a light-emitting element, wherein two ends of the light-emitting element are respectively on the first electrode and the second electrode, The light-emitting element has a shape extending in one direction, and includes a first electrode unit and a second electrode unit respectively located at both ends of the light-emitting element in the one direction, and also includes a conductive ball on the first electrode unit and in direct contact with the first electrode unit, and the second electrode unit is not in contact with any conductive ball.

20. The display device according to claim 19, wherein The light emitting element includes a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer, and The first semiconductor layer, the active layer, and the second semiconductor layer are stacked in another direction perpendicular to the one direction.

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